Method of making automobile top material



April 30, 1963 J. w. RASH 3,087,848

METHOD OF MAKING AUTOMOBILE TOP MATERIAL Filed May 1, 1958 WATEE REPELLENT INVENTOR JOHN W. RASH ATTO R N EY United States Patent 3,087,848METHOD OF MAKING AUTOMOBILE TOP MATERIAL John W. Rash, Westfield, NJL,assignor to Interchemical Corporation, New York, N.Y., a corporation ofOhio Filed May 1, 1953, Ser. No. 732,390 1 Claim. (Cl. 156-280) Thisinvention relates to a combined coated fabric specifically designed foruse as top material for convertible automobiles, and aims to providesuch a coated fabric characterized by excellent resistance to weather,high strength, good flexibility, pleasing appearance and excellent soundabsorption characteristics.

Convertible automobile tops have generally been covered with fabric,which must have certain definite characteristics. It must bewater-repellant to keep out the rain; it must be flexible so that itfolds well when the tops are put up and down; and the fabric must havesufficient mechanical strength to resist accidental impact in theraising and lowering operation.

Originally, heavy waterproofed textile fabrics, either single thicknessor laminated, were used for such tops, generally dyed with vat dyes togive some degree of resistance to fading. Such tops were water-repellantand had the desired flexibility and mechanical strength when new; theyalso had the additional desirable property of absorbing sound. But theydid not stand up well on weathering; the fabric deteriorated under theinfluence of sun, rain and weather, so that such top fabrics requiredreplacing after a relatively short time.

Coated fabrics, which were widely used on fixed tops of automobilesbefore the all-steel bodies came into use, were early suggested aspotential replacements for the simple dyed waterproofed fabrics.However, while coated fabrics are generally substantially moreweatherresistant than uncoated fabrics, the flexibility requirements ofthe convertible top rule out a very large percentage of all coatedfabrics. Most products which are flexible enough unweathered and for afew bendings, lose their flexibility after repeated bendings and/ orweathering. Furthermore, as the fabric structure is built up to givehigher mechanical strength, the overall flexibility of the systemsuffers. In addition, the coating of the fabric, where the coating isdesigned for optimum weather resistance, will often change thecharacteristics of the base fabric, so that the desirable soundabsorption characteristics of the fabric are lost.

It is an object of the present invention to produce a coated fabric foruse in convertible automobile tops which has good mechanical strength,has a permanent pleasing appearance on both sides, is suflicientlyflexible after repeated flexings to be foldable on lowering of the topover long periods of time, is sufficiently waterproof andwater-resistant on both the upper side and the underside to keep outwater over extended periods of use, and yet has the desirable soundabsorption capacity on the inside of the automobile characteristic ofuncoated fabric.

Another object of the present invention is an improved method ofproducing such a fabric characterized by the fact that waterproofing ofthe underside of the fabric, and shrinkage of the complete fabric areobtained with a single treating agent.

According to the present invention, these objects are obtained bycoating-either before or after lamination-a relatively light strongtextile fabric with a pigmented weather-resistant resinous coating,preferably a plasticized polyvinyl chloride coating, preferably appliedby the plastisol method, laminating the coated fabric by the use of anelastomeric adhesive to a second fabric,

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printing the free side of the second fabric with a very thin film ofpigmented ink, preferably in a design simulating a textile, and makingthe uncoated fabric waterrepellant without completely coating thethreads, preferably by applying an aqueous emulsion of an agent whichmakes the fabric water-repellant without forming a continuous coatingover the fabric, rolling the fabric and holding for 4 to 8 hours topermit the water to shrink the structure, and then unrolling and dryingthe fabric without tension thereon.

The resultant coated combined fabric is illustrated in cross-section inthe accompanying drawing. It comprises a weather resistant pigmentedresinous coating 10, preferably a plasticized polyvinyl chloride coatinglaid down by the plastisol process, carried by a textile fabric 12,which is laminated by means of a layer of elastomeric adhesive 14 to atextile fabric 16, which is Waterproofed by a Water repellent agent,which does not coat the textile, but acts despite the open nature of thetextile, the textile bieng decorated with a thin ink film '18,preferably laid down in such a pattern as to resemble an unprinted dyedtextile.

The textile fabrics which are to be combined into the laminated coatedfabric are selected to give the desired strength; they may be of cotton,rayon or synthetic fibers such as nylon, cellulose acetate, Dacronpolyester fiber, and the like. The stronger synthetics, used alone orblended with cotton, give stronger fabrics at equivalent weights andthickness than cotton fabrics. The choice is a matter largely ofeconomics. The weaves are chosen for smoothness and strength-sheetings,drills, twills and sateens are typical.

With cotton fabrics, the finished thickness of the finished coatedfabric will range between about .025 and .040 inch; weightwise, thefabric will represent about 30% to 40% of the composite material.

The topcoating is picked for its original flexibility and its resistanceto weathering; it must retain this flexibility after prolongedweathering and after repeated flexing. Pigmented plasticized polyvinylchloride by which is meant either the homopolyer, or any copolymer withsmall amounts of other materials such as vinyl acetate, maleicanhydride, etc.-is a preferred material. The coatings may be applied tothe top fabric by calendering or controlled solution coating, and thecoated fabric so produced laminated to the second fabric; or the fabricmay be laminated before coating, and the polyvinyl chloride coating beapplied by the plastisol techniquei.e., as a dispersion in aplasticizer, followed by heat to fuse the resin and dissolve it in theplasticizer to form I the desired tough coating.

. binders can be used which have these properties.

The fabrics may be combined with any cured elastomeric adhesive, made ofnatural or any synthetic rubber. These adhesives, when formulated withthe necessary antioxidant and cured, are permanently flexible unlessexposed directly to weathering. In the combined fabric, they areprotected by the polyvinyl chloride topcoat against the direct weatherexposure of the car top and by the water-proofed bottom textile againstthe indirect exposure inside the car. In general, to ease the combining,the adhesives are spread on both fabrics and are then joined face toface with heat and pressure, and cured.

The printing ink used for printing the design on the bottom of thefabric must employ light-fast pigments, and have weather-resistantproperties. A wide range of We have used inks based on Epon resins(bis-phenol epichlorhydrin condensates) on cellulose acetobutyrate, onvarious polyvinyl chloride copolymers, on polyvinylidene chloridecopolymers, on polyacrylate resins of various sorts, and on alkydresins; it appears that if the pigments are light-fast, any binder ofeven moderate weather resistance is adequate to protect the pigmentagainst the relatively mild weather conditions experienced on the bottomside of the fabric. Particularly satisfactory inks are those shown inthe Booth United States Patent 2,691,005, issued October 5, 1954.

It should be noted that the printing ink, which is preferably depositedin a pattern resembling a dyed textile, is so thin and discontinuousthat it provides only a very slight diminution of the sound absorbingcapacity of the fabric.

This desirable feature is retained in the water-repellancy treatment byusing any of the known hydrophobic materials which will give textilematerials waterrepellancy without a continuous coating. Such knownmaterials include wax emulsions and emulsions of water insolublemetallic soaps; somewhat better results are obtainable by treatment withmaterials which give waterrepellancy with somewhat lower concentrationsof agent-- e.g., the chlorosilanes, which convert on the fabric to alkylpolysiloxanes, the stearamidomethyl pyridinium and similar halides(Zelan) and the polymerizable fluorocarbons which are converted on thefabric to water-repellant polymers (e.g., Minnesota Mining Scotchgard PC149).

As indicated above, these water-repellents are preferably applied to thefabric in aqueous dispersion, and the fabric is rolled up and held for 4to 8 hours, following which the fabric is dried without tension (as byfestoonning) to convert the water-repellent to the desired form.Shrinkage control is thus obtained in a single operation together withwater-repellency.

Example I In a typical process for practicing the invention, a 2.10cotton sheeting (2.10 linear yards per pound ona 56 inch width basis) ofa thread count 64 x 64, using #21 carded cotton yarn for the warp and#25 carded cotton yarn for the fill, was employed as top sheet, and a1.95 cotton drill, 68 x 40 count, with a #21 warp and #14- fill, wasemployed as the bottom sheet.

Each of the fabrics was coated with an adhesive com-' position havingthe following formula, using a total of 9 ounces adhesive (solid basis)per linear yard (56 inches wide) of combined material:

Lbs. Ozs

Eniay Butyl #268 (Bntyl rubber) 50 Soft Clay 37 0 Silene (Calciumsilicate) 2 8 Zinc Oxide. 2 8 Sulfur l2 Altax (Benzothiazyl snlfide).. 4Methyl Zimate (Zinc dimethyl dithiocarbamate) 8 Staybelite Resin(Stabilized rosin) 12 Aluminum Stenratc l 0 Titanium Dioxide 5 0 The twosheets were laminated together by passing between a steel and rubberroller, under pressure; curing took place partially by heating therolls, and partially in the remainder of the process.

The combined sheet was coated with a vinyl plastisol, using about 13.5ounces per'linear yard of 56 inch material and of the followingcomposition:

Parts by weight Pigment dispersion-55% TiO 45% Flexol 8N8--- 10% vinylacetate) 10 Acryloid A101 (40% solution of polymethyl methacrylate inmethyl ethyl ketone) 11 Paraplex G50 (Rohm & Haas-polymeric polyesterplasticizer) 5 Heat and light stabilizer for polyvinyl chloride (as inthe vinyl plastisol) /z Solvent (half acetone-half toluene) 55 /2 Thedesign was an engraved gravure plate simulating a textile weave, givingthe underside of the fabric the appearance of a dyed fabric.

Finally, the fabric was padded with a thin aqueous dispersion of awater-repellant agent-Arkansas Chemical Companys clear. Hydropruf, whichis a chlorosilanc which converts on the fabric to an alkyl polysiloxane(4% solids as applied). The wet fabric was rolled, and held 6 hours; itwas then dried without tension, in a festooned rack, at a temperature of220 F.

The resultant fabric is strong, flexible, weather resistant afterprolonged use, and the underside has the appearance and desirable soundabsorbency properties of ordinary fabric for the inside of an automobilewhen the top is up; at the same time, the underside will not fade ordeteriorate in the manner of ordinary dyed underside fabrics of theprior art.

Example 11 Instead of proceeding as above, the top fabric may be coatedfirst, and then combined. Thus, using the same fabric as in the aboveexample, the 2.10 cotton sheeting was coated by calendaring on 14 ouncesper linear yard of 56 inch material of a composition comprising:

Part by weight Vinylite VYNS (copoly-mer of vinyl chloride,

The calendered coated fabric was combined with the 1.95 drill as inExample I, or it may be combined by usmg a rubber cement made bycompounding, on a rubber mill Part by weight Smoked sheets (naturalrubber) 57.5 Clay 23.0 Zinc oxide 2.8 Benzothiazyl disulfide 0.6 Zincdibutyl thiocarbamate 0.05 Antioxidant [2-2 methylene bis(4 methyl 6tertiary butyl phenol)] 1.20

Titanium dioxide 14.00

and dissolving this compound in the ratio of 35 parts by weight compoundto 35 parts by weight of any suitable solvent, such as a gasoline rangepetroleum distillate. The cement is coated on both fabrics, allowed tobecome tacky, and the fabrics combined as in Example I; the rubbercement is partially cured in combining, partially during furtherprocessing.

In this example, the inner fabric was printed with an ink made inaccordance with the Booth Patent 2,691,005, issued October 5, 1954; theink was set by heating the fabric, which heat acted also to help curethe rubber cement.

The fabric was made water-repellent by treatment with aqueous zirconiumacetate, in conventional fashion; the wet fabric was treated as inExample I, to shrink the fabric along with the water control treatment.

The above examples can be carried out with preshrunk fabric, in whichcase no care need be exercised in the drying of the Wet combined fabric.The resinous topcoating employed may be applied as plastisol or bycalendering, or it may be applied by coating solutions of resins, usinga multiplicity of coats to build up the desired film thickness. Anyweather resistant resinous coating can be used, the preferred coatingsbeing of polyvinyl chloride (including copolymers with minor portions ofactive ingredients). Further, as indicated above, various adhesive maybe used, as long as they are of curable elastomeric material, and anylight-fast inks may be employed, which do not completely coat thefabric.

Obviously, the examples given above are not exhaustive and can be widelymodified, as indicated above, by utilizing any of the topcoats,adhesives or inks which have been indicated as useful, without departingfrom the invention which is defined in the claim.

What is claimed is:

The method of producing convertible automobile top material whichcomprises preparing a combined fabric comprising two woven textilefabrics united by an elastomeric adhesive and coated on one face with aweatherresistant pigmented plasticized polyvinyl chloride coating,printing the back of the combined fabric with a lightresistant ink,soaking the back of the fabric in an aqueous dispersion of an agentcapable of making the fabric back water-repellent without producing acontinuous coating, rolling up the wet fabric, holding it rolled for 4to 8 hours, and finally unrolling and heating while free of tension todrive out the water to simultaneously shrink the composite fabric andset the water-repellent agents.

References Cited in the file of this patent UNITED STATES PATENTS815,307 Odell Mar. 13, 1906 \1,-18 5,067 Colburn May 30, 19 16 2,098,754Nickowitz Nov. 9, 1937 2,431,745 Flanagan Dec. 2, 1947 2,527,299 DePhillips Oct. 24, 1950 2,533,976 Teague Dec. 12, 1950 2,779,035 McMunryJan. 29, 1957

